How could I make a tool that morphs other players?

I want to make a tool that, when you click other players, would morph their character into a new one.
I want the script to act like this, in a way, but with a tool and changing the clothes, as well as adding accessories. Example - YouTube
What could I do to make this happen, or what should I refer to while doing it?

I don’t have a clue where to start with this, any references would be very much appreciated!

Easiest way to do this would be to check if the mouse is on top of a player a tool.Activated function (Tool | Roblox Creator Documentation) then going from there. You would use mouse.Target for this (Mouse | Roblox Creator Documentation). After you have a script setup that detects players when you click on them with the tool you can look up pretty much any clothing/accessory changing tutorial and merge the code from that with yours.

As SquidyCakez said, use tool.Activated and mouse.Target. Other than that, send over the targeted character and change the humanoid’s description through a remote event.

if on my step:
1.get the mouse
2.find the humanoid
3.if state 2 is correct, continue
4.get all player in players
5.use player.Character and check if that character is the same as the target mouse character
6.if state 5 is correct, continue
7.now you got a player character appearance which is the id, set our player id to his/her id
8.respawn the player

NOTE:after you respawn a player, it will stay there forever, i think you can change back by using our player id.

I used this method, and got it working correctly. Thanks!